Mathematics and Society - OS X Lion Server

The moon, our largest satellite and the second brightest object in our sky, hashad much influence on our lives. As we watch it throughout the year, the shape of thelighted portion seen from earth changes nightly, but each lighted shape seems to reoccurperiodically. This periodic change in appearance was used by our ancestors tomeasure intervals of time and is the natural unit on which our calendar month isbased. You are probably familiar with the use of the lunar month by American Indians.They measured the duration of trips and other lengthy events by counting the numberof moons that passed--by which they meant complete lunar cycles--before the event wascompleted.Why does the moon's appearance change?predict the moon's approximate location ineightFigure Ishows the moon inpositions in its 29y,-dayorbit around the earth.is off to the righture and lights halfThe sunof the figofthe earthand the moon at each position asshown.the moon,For each position ofpredict its phase(how it appears to you on earth)and sketch your predictions inthe small boxes just outsideFor each time of day is it possible tothe sky if you know its shape (phase)?WAltII-lG GI BBOUSDF'R.$TQUARTERD /---(}.~ ~.«\',, , ,'~ Wft,XII\lG~ U CRESCEI\lT 4011---o () ~'13~ ~+--.0-'---·-FULL \ " NEW SUI.lS, ~ ,loll\ / RAYS'(), ,,(5/ .-.--DWA~t)-_// Dthe moon's orbit. The waxingGIBBOUSWAtJ\t-JGcrescent has been done for you.DTHIRD CRESCEI\lTI'"IGURE. 1 QUARTER ...HOlDT~~~To check your predictions stand about six8ALL SLIGHTLYfeet from a bright flashlight (the sun) in anABOVE YOUR HEAD SOotherwise darkened room. Hold a tennis ball atYOUR BODY DOES "lOTarms length and turn your body very slowlySlOCK THE: LIGHT.while holding your arm steady. The shapes oflighted portions of the ball that you can seewill correspond to the phases of the moon.FIGURE. 2.79